The upper() method converts all lowercase characters in a string into uppercase characters and returns it.
Example
message = 'python is fun'# convert message to uppercase print(message.upper())
# Output: PYTHON IS FUNSyntax of String upper()
The syntax of upper() method is:
string.upper()upper() Parameters
upper() method doesn't take any parameters.
upper() Return Value
upper() method returns the uppercase string from the given string. It converts all lowercase characters to uppercase.
If no lowercase characters exist, it returns the original string.
Example 1: Convert a string to uppercase
# example string string = "this should be uppercase!"print(string.upper())
# string with numbers # all alphabets should be lowercase string = "Th!s Sh0uLd B3 uPp3rCas3!"print(string.upper())
Output
THIS SHOULD BE UPPERCASE! TH!S SH0ULD B3 UPP3RCAS3!Example 2: How upper() is used in a program?
# first string firstString = "python is awesome!" # second string secondString = "PyThOn Is AwEsOmE!"if(firstString.upper() == secondString.upper()):
print("The strings are same.") else: print("The strings are not same.")Output
The strings are same.Note: If you want to convert to lowercase string, use lower(). You can also use swapcase() to swap between lowercase to uppercase.
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String.ToLower Method
- Reference
Definition
Returns a copy of this string converted to lowercase.
In this article
Overloads
ToLower() | Returns a copy of this string converted to lowercase. |
ToLower(CultureInfo) | Returns a copy of this string converted to lowercase, using the casing rules of the specified culture. |
ToLower()
Returns a copy of this string converted to lowercase.
public: System::String ^ ToLower();public string ToLower ();member this.ToLower : unit -> stringPublic Function ToLower () As StringReturns
StringA string in lowercase.
Examples
The following example converts several mixed case strings to lowercase.
using namespace System; using namespace System::Collections; int main() { array<String^>^info = {"Name","Title","Age","Location","Gender"}; Console::WriteLine( "The initial values in the array are:" ); IEnumerator^ myEnum = info->GetEnumerator(); while ( myEnum->MoveNext() ) { String^ s = safe_cast<String^>(myEnum->Current); Console::WriteLine( s ); } Console::WriteLine( " {0}The lowercase of these values is:", Environment::NewLine ); IEnumerator^ myEnum1 = info->GetEnumerator(); while ( myEnum1->MoveNext() ) { String^ s = safe_cast<String^>(myEnum1->Current); Console::WriteLine( s->ToLower() ); } Console::WriteLine( " {0}The uppercase of these values is:", Environment::NewLine ); IEnumerator^ myEnum2 = info->GetEnumerator(); while ( myEnum2->MoveNext() ) { String^ s = safe_cast<String^>(myEnum2->Current); Console::WriteLine( s->ToUpper() ); } } // The example displays the following output: // The initial values in the array are: // Name // Title // Age // Location // Gender // // The lowercase of these values is: // name // title // age // location // gender // // The uppercase of these values is: // NAME // TITLE // AGE // LOCATION // GENDER using System; public class ToLowerTest { public static void Main() { string [] info = {"Name", "Title", "Age", "Location", "Gender"}; Console.WriteLine("The initial values in the array are:"); foreach (string s in info) Console.WriteLine(s); Console.WriteLine("{0}The lowercase of these values is:", Environment.NewLine); foreach (string s in info) Console.WriteLine(s.ToLower()); Console.WriteLine("{0}The uppercase of these values is:", Environment.NewLine); foreach (string s in info) Console.WriteLine(s.ToUpper()); } } // The example displays the following output: // The initial values in the array are: // Name // Title // Age // Location // Gender // // The lowercase of these values is: // name // title // age // location // gender // // The uppercase of these values is: // NAME // TITLE // AGE // LOCATION // GENDER open System let info = [| "Name"; "Title"; "Age"; "Location"; "Gender" |] printfn "The initial values in the array are:" for s in info do printfn $"{s}" printfn $"{Environment.NewLine}The lowercase of these values is:" for s in info do printfn $"{s.ToLower()}" printfn $"{Environment.NewLine}The uppercase of these values is:" for s in info do printfn $"{s.ToUpper()}" // The example displays the following output: // The initial values in the array are: // Name // Title // Age // Location // Gender // // The lowercase of these values is: // name // title // age // location // gender // // The uppercase of these values is: // NAME // TITLE // AGE // LOCATION // GENDER Public Class ToLowerTest Public Shared Sub Main() Dim info As String() = {"Name", "Title", "Age", "Location", "Gender"} Console.WriteLine("The initial values in the array are:") Dim s As String For Each s In info Console.WriteLine(s) Next Console.WriteLine("{0}The lowercase of these values is:", Environment.NewLine) For Each s In info Console.WriteLine(s.ToLower()) Next Console.WriteLine("{0}The uppercase of these values is:", Environment.NewLine) For Each s In info Console.WriteLine(s.ToUpper()) Next End Sub End Class ' The example displays the following output: ' The initial values in the array are: ' Name ' Title ' Age ' Location ' Gender ' ' The lowercase of these values is: ' name ' title ' age ' location ' gender ' ' The uppercase of these values is: ' NAME ' TITLE ' AGE ' LOCATION ' GENDERRemarks
This method takes into account the casing rules of the current culture.
Note
This method does not modify the value of the current instance. Instead, it returns a new string in which all characters in the current instance are converted to lowercase.
Security Considerations
The casing operation that results from calling the ToLower() method takes the casing conventions of the current culture into account. If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant methods. This produces the same result in every culture (unlike the ToLower() method) and performs more efficiently.
Notes to Callers
As explained in Best Practices for Using Strings, we recommend that you avoid calling string casing methods that substitute default values and instead call methods that require parameters to be explicitly specified. To convert a character to lowercase by using the casing conventions of the current culture, call the ToLower(CultureInfo) method overload with a value of CurrentCulture for its culture parameter.
See also
- ToLowerInvariant()
- ToUpper()
- ToUpperInvariant()
Applies to
ToLower(CultureInfo)
Returns a copy of this string converted to lowercase, using the casing rules of the specified culture.
public: System::String ^ ToLower(System::Globalization::CultureInfo ^ culture);public string ToLower (System.Globalization.CultureInfo? culture);public string ToLower (System.Globalization.CultureInfo culture);member this.ToLower : System.Globalization.CultureInfo -> stringPublic Function ToLower (culture As CultureInfo) As StringParameters
culture CultureInfo
An object that supplies culture-specific casing rules. If culture is null, the current culture is used.
Returns
StringThe lowercase equivalent of the current string.
Examples
The following example converts two strings of uppercase characters to lowercase characters using the English-United States and Turkish-Turkey cultures, then compares the lowercase strings. The uppercase strings are identical except that for each occurrence of the Unicode LATIN CAPITAL LETTER I in one string, the other string contains LATIN CAPITAL LETTER I WITH DOT ABOVE.
// Sample for String::ToLower(CultureInfo) using namespace System; using namespace System::Globalization; void CodePoints( String^ title, String^ s ) { Console::Write( "{0}The code points in {1} are: {0}", Environment::NewLine, title ); System::Collections::IEnumerator^ myEnum = s->GetEnumerator(); while ( myEnum->MoveNext() ) { UInt16 u = safe_cast<Char>(myEnum->Current); Console::Write( "{0:x4} ", u ); } Console::WriteLine(); } int main() { String^ str1 = "INDIGO"; // str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE). array<Char>^temp = {L'\u0130',L'N',L'D',L'\u0130',L'G',L'O'}; String^ str2 = gcnew String( temp ); String^ str3; String^ str4; Console::WriteLine(); Console::WriteLine( "str1 = '{0}'", str1 ); Console::WriteLine(); Console::WriteLine( "str1 is {0} to str2.", ((0 == String::CompareOrdinal( str1, str2 )) ? (String^)"equal" : "not equal") ); CodePoints( "str1", str1 ); CodePoints( "str2", str2 ); Console::WriteLine(); // str3 is a lower case copy of str2, using English-United States culture. Console::WriteLine( "str3 = Lower case copy of str2 using English-United States culture." ); str3 = str2->ToLower( gcnew CultureInfo( "en-US",false ) ); // str4 is a lower case copy of str2, using Turkish-Turkey culture. Console::WriteLine( "str4 = Lower case copy of str2 using Turkish-Turkey culture." ); str4 = str2->ToLower( gcnew CultureInfo( "tr-TR",false ) ); // Compare the code points in str3 and str4. Console::WriteLine(); Console::WriteLine( "str3 is {0} to str4.", ((0 == String::CompareOrdinal( str3, str4 )) ? (String^)"equal" : "not equal") ); CodePoints( "str3", str3 ); CodePoints( "str4", str4 ); } /* This example produces the following results: str1 = 'INDIGO' str1 is not equal to str2. The code points in str1 are: 0049 004e 0044 0049 0047 004f The code points in str2 are: 0130 004e 0044 0130 0047 004f str3 = Lower case copy of str2 using English-United States culture. str4 = Lower case copy of str2 using Turkish-Turkey culture. str3 is equal to str4. The code points in str3 are: 0069 006e 0064 0069 0067 006f The code points in str4 are: 0069 006e 0064 0069 0067 006f */ // Sample for String.ToLower(CultureInfo) using System; using System.Globalization; class Sample { public static void Main() { String str1 = "INDIGO"; // str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE). String str2 = new String(new Char[] {'\u0130', 'N', 'D', '\u0130', 'G', 'O'}); String str3, str4; Console.WriteLine(); Console.WriteLine("str1 = '{0}'", str1); Console.WriteLine(); Console.WriteLine("str1 is {0} to str2.", ((0 == String.CompareOrdinal(str1, str2)) ? "equal" : "not equal")); CodePoints("str1", str1); CodePoints("str2", str2); Console.WriteLine(); // str3 is a lower case copy of str2, using English-United States culture. Console.WriteLine("str3 = Lower case copy of str2 using English-United States culture."); str3 = str2.ToLower(new CultureInfo("en-US", false)); // str4 is a lower case copy of str2, using Turkish-Turkey culture. Console.WriteLine("str4 = Lower case copy of str2 using Turkish-Turkey culture."); str4 = str2.ToLower(new CultureInfo("tr-TR", false)); // Compare the code points in str3 and str4. Console.WriteLine(); Console.WriteLine("str3 is {0} to str4.", ((0 == String.CompareOrdinal(str3, str4)) ? "equal" : "not equal")); CodePoints("str3", str3); CodePoints("str4", str4); } public static void CodePoints(String title, String s) { Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title); foreach (ushort u in s) Console.Write("{0:x4} ", u); Console.WriteLine(); } } /* This example produces the following results: str1 = 'INDIGO' str1 is not equal to str2. The code points in str1 are: 0049 004e 0044 0049 0047 004f The code points in str2 are: 0130 004e 0044 0130 0047 004f str3 = Lower case copy of str2 using English-United States culture. str4 = Lower case copy of str2 using Turkish-Turkey culture. str3 is equal to str4. The code points in str3 are: 0069 006e 0064 0069 0067 006f The code points in str4 are: 0069 006e 0064 0069 0067 006f */ // Sample for String.ToLower(CultureInfo) open System open System.Globalization let codePoints title s = printf $"{Environment.NewLine}The code points in {title} are: {Environment.NewLine}" for u in s do printf $"{u:x4} " printfn "" let str1 = "INDIGO" // str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE). let str2 = String [| '\u0130'; 'N'; 'D'; '\u0130'; 'G'; 'O' |] printfn $"\nstr1 = '{str1}'\n" printfn $"""str1 is {if 0 = String.CompareOrdinal(str1, str2) then "equal" else "not equal"} to str2.""" codePoints "str1" str1 codePoints "str2" str2 // str3 is a lower case copy of str2, using English-United States culture. printfn "\nstr3 = Lower case copy of str2 using English-United States culture." let str3 = str2.ToLower(CultureInfo("en-US", false)) // str4 is a lower case copy of str2, using Turkish-Turkey culture. printfn "str4 = Lower case copy of str2 using Turkish-Turkey culture." let str4 = str2.ToLower(CultureInfo("tr-TR", false)) // Compare the code points in str3 and str4. printfn $"""\nstr3 is {if 0 = String.CompareOrdinal(str3, str4) then "equal" else "not equal"} to str4.""" codePoints "str3" str3 codePoints "str4" str4 (* This example produces the following results: str1 = 'INDIGO' str1 is not equal to str2. The code points in str1 are: 0049 004e 0044 0049 0047 004f The code points in str2 are: 0130 004e 0044 0130 0047 004f str3 = Lower case copy of str2 using English-United States culture. str4 = Lower case copy of str2 using Turkish-Turkey culture. str3 is equal to str4. The code points in str3 are: 0069 006e 0064 0069 0067 006f The code points in str4 are: 0069 006e 0064 0069 0067 006f *) ' Sample for String.ToLower(CultureInfo) Imports System.Globalization Class Sample Public Shared Sub Main() Dim str1 As [String] = "INDIGO" ' str2 = str1, except each 'I' is '\u0130' (Unicode LATIN CAPITAL I WITH DOT ABOVE). Dim str2 As New [String](New [Char]() {ChrW(&H0130), "N"c, "D"c, ChrW(&H0130), "G"c, "O"c}) Dim str3, str4 As [String] Console.WriteLine() Console.WriteLine("str1 = '{0}'", str1) Console.WriteLine() Console.WriteLine("str1 is {0} to str2.", _ IIf(0 = [String].CompareOrdinal(str1, str2), "equal", "not equal")) CodePoints("str1", str1) CodePoints("str2", str2) Console.WriteLine() ' str3 is a lower case copy of str2, using English-United States culture. Console.WriteLine("str3 = Lower case copy of str2 using English-United States culture.") str3 = str2.ToLower(New CultureInfo("en-US", False)) ' str4 is a lower case copy of str2, using Turkish-Turkey culture. Console.WriteLine("str4 = Lower case copy of str2 using Turkish-Turkey culture.") str4 = str2.ToLower(New CultureInfo("tr-TR", False)) ' Compare the code points in str3 and str4. Console.WriteLine() Console.WriteLine("str3 is {0} to str4.", _ IIf(0 = [String].CompareOrdinal(str3, str4), "equal", "not equal")) CodePoints("str3", str3) CodePoints("str4", str4) End Sub Public Shared Sub CodePoints(title As [String], s As [String]) Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title) Dim c As Char For Each c In s Console.Write("{0:x4} ", AscW(c)) Next c Console.WriteLine() End Sub End Class ' 'str1 = 'INDIGO' ' 'str1 is not equal to str2. ' 'The code points in str1 are: '0049 004e 0044 0049 0047 004f ' 'The code points in str2 are: '0130 004e 0044 0130 0047 004f ' 'str3 = Lower case copy of str2 using English-United States culture. 'str4 = Lower case copy of str2 using Turkish-Turkey culture. ' 'str3 is equal to str4. ' 'The code points in str3 are: '0069 006e 0064 0069 0067 006f ' 'The code points in str4 are: '0069 006e 0064 0069 0067 006fRemarks
The casing rules of the culture specified by the culture parameter determine the way the case of the string is changed.
Note
This method does not modify the value of the current instance. Instead, it returns a new string in which all characters in the current instance are converted to lowercase.
Security Considerations
If you pass the ToLower(CultureInfo) method a CultureInfo object other than CultureInfo.InvariantCulture, the casing operation will take culture-specific rules into account. If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant method. This produces the same result in every culture and performs more efficiently.
See also
- CultureInfo
- ToUpper()